Ground support apparatus and methods using combined mechanical and chemical means are well known in the mining, tunneling and construction industries. Basically, a hole is drilled in the surrounding rock formation from unstable to stable strata. Packaged resin compounds are inserted into the drilled hole. A ground support member is then inserted into the drilled hole which punctures and mixes the resin packages.
The member is rotated to ensure that the resin mixes and fills the annulus between the member and the inside surface of the drilled hole. The resin hardens and then the member is tensioned to a predetermined load. To facilitate the ground support operation, a variety of machines have been proposed to insert the ground support member into the drill hole. One such machine is described in application CA 2460497 Rebar Insertion Device by John Fifield filed on 2004 Mar. 9. This device works well in many ground support applications but it has a number of weaknesses that have become apparent from field use.
For example, a significant amount of force is required to push a ground support member into a pre-drilled hole and through packaged resin. This force is applied by the pusher leg or jackleg which is a pneumatic or hydraulic piston to which the drill is attached. As this force is applied to the ground support member, lateral forces are created in the pusher leg and in the supports of the pusher leg which have been found to destabilize the apparatus because it is not supported for these loads. This causes the jackleg drill and pusher leg to move and swivel, which can damage the ground support member and may create a worker hazard.
Therefore there is a need to resolve this problem to prevent damage to the ground support member which may compromise its structural integrity and to discourage injury to the drill operator.